Glass containers, such as bottles and jars, frequently are used in the packaging of liquids which may leach the alkali out of the interior surface of the glass structure. In order to avoid this leaching and the resultant appearance of contamination of the liquid to be contained in the bottle, it has been the practice in the past to internally treat the glassware with an acidic gas. Such gases, for example, have been sulfur dioxide or trioxide and it has been the practice to accomplish this internal acidic gas treatment by placing pellets of sulfur in the hot bottles as they are moving from the glass forming machine to the annealing lehr. At this stage of the process of formation of the glass bottles, the containers are sufficiently hot to cause the sulfur to vaporize and thereby create an acidic gas which neutralizes the alkalinity of the interior glass surface. One such prior art patent teaches the addition of sulfur pellets to hot bottles as they are moving from the forming machine to the annealing lehr. This patent is to U. E. Bowes, U.S. Pat. No. 2,046,302, issued June 30, 1936. Another system accomplishing a similar result is disclosed in application Ser. No. 571,149 filed Apr. 24, 1975, in which pellets that have been delivered to a gating device are positioned by the gating device into a delivery tube and then pneumatically delivered to the interior of the containers. The present invention, in effect, constitutes an improvement in the gating mechanism which will permit the pellets to be isolated and then delivered with a minimum of mechanical movement and with the operation of a single pneumatic plunger.